#include "apue.h"
#include "pr_mask.c"
#include <setjmp.h>
#include <time.h>

static void sig_usr1(int);
static void sig_alrm(int);

static sigjmp_buf               jmpbuf;
static volatile sig_atomic_t    canjump;

int 
main(void)
{
    if (signal(SIGUSR1, sig_usr1) == SIG_ERR)
        err_sys("signal(SIGUSR1) error");
    if (signal(SIGALRM, sig_alrm) == SIG_ERR)
        err_sys("signal(SIGALRM) error");

    pr_mask("starting main: ");     /* {Prog prmask} */

    if (sigsetjmp(jmpbuf, 1)) {
        pr_mask("ending main: ");
        exit(0);
    }
    canjump = 1;    /* now sigsetjmp() is OK */

    for ( ; ; )
        pause();
}

static void 
sig_usr1(int signo)
{
    time_t starttime;

    if (canjump == 0)
        return;     /* unexpected signal, ignore */

    pr_mask("starting sig_usr1: ");

    alarm(3);               /* SIGALRM in 3 seconds */
    starttime = time(NULL);
    for ( ; ; )             /* busy wait for 5 seconds */
        if (time(NULL) > starttime + 5)
            break;

    pr_mask("finishing sig_usr1: ");

    canjump = 0;
    siglongjmp(jmpbuf, 1);  /* jump back to main, don't return */
}

static void 
sig_alrm(int signo)
{
    pr_mask("in sig_alrm: ");
}
